diff --git a/jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListMap.java b/jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListMap.java
index 2ae29aa42f3..d34c74cd9a9 100644
--- a/jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListMap.java
+++ b/jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListMap.java
@@ -48,7 +48,6 @@ import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
-import java.util.NavigableMap;
 import java.util.NavigableSet;
 import java.util.NoSuchElementException;
 import java.util.Set;
diff --git a/jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListSet.java b/jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListSet.java
index 86be622c78b..ccd7f647d83 100644
--- a/jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListSet.java
+++ b/jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListSet.java
@@ -43,7 +43,6 @@ import java.util.Collections;
 import java.util.Comparator;
 import java.util.Iterator;
 import java.util.Map;
-import java.util.NavigableMap;
 import java.util.NavigableSet;
 import java.util.Set;
 import java.util.SortedSet;
diff --git a/jdk/src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java b/jdk/src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java
index 330f4fb78a3..d8697970586 100644
--- a/jdk/src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java
+++ b/jdk/src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java
@@ -2354,7 +2354,7 @@ public class ForkJoinPool extends AbstractExecutorService {
         checkPermission();
     }
 
-    private Object newInstanceFromSystemProperty(String property)
+    private static Object newInstanceFromSystemProperty(String property)
         throws ReflectiveOperationException {
         String className = System.getProperty(property);
         return (className == null)
@@ -2524,15 +2524,13 @@ public class ForkJoinPool extends AbstractExecutorService {
      * @throws RejectedExecutionException if the task cannot be
      *         scheduled for execution
      */
+    @SuppressWarnings("unchecked")
     public ForkJoinTask<?> submit(Runnable task) {
         if (task == null)
             throw new NullPointerException();
-        ForkJoinTask<?> job;
-        if (task instanceof ForkJoinTask<?>) // avoid re-wrap
-            job = (ForkJoinTask<?>) task;
-        else
-            job = new ForkJoinTask.AdaptedRunnableAction(task);
-        return externalSubmit(job);
+        return externalSubmit((task instanceof ForkJoinTask<?>)
+            ? (ForkJoinTask<Void>) task // avoid re-wrap
+            : new ForkJoinTask.AdaptedRunnableAction(task));
     }
 
     /**
diff --git a/jdk/src/java.base/share/classes/java/util/concurrent/ForkJoinWorkerThread.java b/jdk/src/java.base/share/classes/java/util/concurrent/ForkJoinWorkerThread.java
index a3054b865ba..b1550f9f648 100644
--- a/jdk/src/java.base/share/classes/java/util/concurrent/ForkJoinWorkerThread.java
+++ b/jdk/src/java.base/share/classes/java/util/concurrent/ForkJoinWorkerThread.java
@@ -203,21 +203,19 @@ public class ForkJoinWorkerThread extends Thread {
     static final class InnocuousForkJoinWorkerThread extends ForkJoinWorkerThread {
         /** The ThreadGroup for all InnocuousForkJoinWorkerThreads */
         private static final ThreadGroup innocuousThreadGroup =
-            java.security.AccessController.doPrivileged(
-                new java.security.PrivilegedAction<>() {
-                    public ThreadGroup run() {
-                        ThreadGroup group = Thread.currentThread().getThreadGroup();
-                        for (ThreadGroup p; (p = group.getParent()) != null; )
-                            group = p;
-                        return new ThreadGroup(group, "InnocuousForkJoinWorkerThreadGroup");
-                    }});
+            AccessController.doPrivileged(new PrivilegedAction<>() {
+                public ThreadGroup run() {
+                    ThreadGroup group = Thread.currentThread().getThreadGroup();
+                    for (ThreadGroup p; (p = group.getParent()) != null; )
+                        group = p;
+                    return new ThreadGroup(
+                        group, "InnocuousForkJoinWorkerThreadGroup");
+                }});
 
         /** An AccessControlContext supporting no privileges */
         private static final AccessControlContext INNOCUOUS_ACC =
             new AccessControlContext(
-                new ProtectionDomain[] {
-                    new ProtectionDomain(null, null)
-                });
+                new ProtectionDomain[] { new ProtectionDomain(null, null) });
 
         InnocuousForkJoinWorkerThread(ForkJoinPool pool) {
             super(pool,
diff --git a/jdk/src/java.base/share/classes/java/util/concurrent/locks/ReentrantReadWriteLock.java b/jdk/src/java.base/share/classes/java/util/concurrent/locks/ReentrantReadWriteLock.java
index ab43971e84d..4f093bf5631 100644
--- a/jdk/src/java.base/share/classes/java/util/concurrent/locks/ReentrantReadWriteLock.java
+++ b/jdk/src/java.base/share/classes/java/util/concurrent/locks/ReentrantReadWriteLock.java
@@ -444,7 +444,7 @@ public class ReentrantReadWriteLock
             }
         }
 
-        private IllegalMonitorStateException unmatchedUnlockException() {
+        private static IllegalMonitorStateException unmatchedUnlockException() {
             return new IllegalMonitorStateException(
                 "attempt to unlock read lock, not locked by current thread");
         }
diff --git a/jdk/test/java/util/concurrent/tck/ArrayDeque8Test.java b/jdk/test/java/util/concurrent/tck/ArrayDeque8Test.java
index 0a7f26bfe64..c2079555218 100644
--- a/jdk/test/java/util/concurrent/tck/ArrayDeque8Test.java
+++ b/jdk/test/java/util/concurrent/tck/ArrayDeque8Test.java
@@ -37,7 +37,6 @@ import java.util.Collections;
 import java.util.Spliterator;
 
 import junit.framework.Test;
-import junit.framework.TestSuite;
 
 public class ArrayDeque8Test extends JSR166TestCase {
     public static void main(String[] args) {
diff --git a/jdk/test/java/util/concurrent/tck/ArrayDequeTest.java b/jdk/test/java/util/concurrent/tck/ArrayDequeTest.java
index 1bbd98106ac..344b63c9b79 100644
--- a/jdk/test/java/util/concurrent/tck/ArrayDequeTest.java
+++ b/jdk/test/java/util/concurrent/tck/ArrayDequeTest.java
@@ -35,7 +35,6 @@
 import java.util.ArrayDeque;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Deque;
 import java.util.Iterator;
 import java.util.NoSuchElementException;
@@ -44,7 +43,6 @@ import java.util.Random;
 import java.util.concurrent.ThreadLocalRandom;
 
 import junit.framework.Test;
-import junit.framework.TestSuite;
 
 public class ArrayDequeTest extends JSR166TestCase {
     public static void main(String[] args) {
diff --git a/jdk/test/java/util/concurrent/tck/ArrayListTest.java b/jdk/test/java/util/concurrent/tck/ArrayListTest.java
index 193b4af8aca..535f04d34b5 100644
--- a/jdk/test/java/util/concurrent/tck/ArrayListTest.java
+++ b/jdk/test/java/util/concurrent/tck/ArrayListTest.java
@@ -33,11 +33,9 @@
  */
 
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.List;
 
 import junit.framework.Test;
-import junit.framework.TestSuite;
 
 public class ArrayListTest extends JSR166TestCase {
     public static void main(String[] args) {
diff --git a/jdk/test/java/util/concurrent/tck/AtomicReferenceFieldUpdaterTest.java b/jdk/test/java/util/concurrent/tck/AtomicReferenceFieldUpdaterTest.java
index fb50658ea91..5fdf279238c 100644
--- a/jdk/test/java/util/concurrent/tck/AtomicReferenceFieldUpdaterTest.java
+++ b/jdk/test/java/util/concurrent/tck/AtomicReferenceFieldUpdaterTest.java
@@ -75,7 +75,7 @@ public class AtomicReferenceFieldUpdaterTest extends JSR166TestCase {
             assertTrue(a.compareAndSet(this, two, m4));
             assertSame(m4, a.get(this));
             assertFalse(a.compareAndSet(this, m5, seven));
-            assertFalse(seven == a.get(this));
+            assertNotSame(seven, a.get(this));
             assertTrue(a.compareAndSet(this, m4, seven));
             assertSame(seven, a.get(this));
         }
@@ -208,7 +208,7 @@ public class AtomicReferenceFieldUpdaterTest extends JSR166TestCase {
         assertTrue(a.compareAndSet(this, two, m4));
         assertSame(m4, a.get(this));
         assertFalse(a.compareAndSet(this, m5, seven));
-        assertFalse(seven == a.get(this));
+        assertNotSame(seven, a.get(this));
         assertTrue(a.compareAndSet(this, m4, seven));
         assertSame(seven, a.get(this));
     }
diff --git a/jdk/test/java/util/concurrent/tck/AtomicReferenceTest.java b/jdk/test/java/util/concurrent/tck/AtomicReferenceTest.java
index 6242374ee89..eb8c0b7b565 100644
--- a/jdk/test/java/util/concurrent/tck/AtomicReferenceTest.java
+++ b/jdk/test/java/util/concurrent/tck/AtomicReferenceTest.java
@@ -153,7 +153,7 @@ public class AtomicReferenceTest extends JSR166TestCase {
         AtomicReference z = serialClone(x);
         assertNotSame(y, z);
         assertEquals(one, x.get());
-        assertEquals(null, y.get());
+        assertNull(y.get());
         assertEquals(one, z.get());
     }
 
diff --git a/jdk/test/java/util/concurrent/tck/CompletableFutureTest.java b/jdk/test/java/util/concurrent/tck/CompletableFutureTest.java
index 6def2fffb3a..6439a40fcb0 100644
--- a/jdk/test/java/util/concurrent/tck/CompletableFutureTest.java
+++ b/jdk/test/java/util/concurrent/tck/CompletableFutureTest.java
@@ -2589,28 +2589,28 @@ public class CompletableFutureTest extends JSR166TestCase {
 
         // unspecified behavior - both source completions available
         try {
-            assertEquals(null, h0.join());
+            assertNull(h0.join());
             rs[0].assertValue(v1);
         } catch (CompletionException ok) {
             checkCompletedWithWrappedException(h0, ex);
             rs[0].assertNotInvoked();
         }
         try {
-            assertEquals(null, h1.join());
+            assertNull(h1.join());
             rs[1].assertValue(v1);
         } catch (CompletionException ok) {
             checkCompletedWithWrappedException(h1, ex);
             rs[1].assertNotInvoked();
         }
         try {
-            assertEquals(null, h2.join());
+            assertNull(h2.join());
             rs[2].assertValue(v1);
         } catch (CompletionException ok) {
             checkCompletedWithWrappedException(h2, ex);
             rs[2].assertNotInvoked();
         }
         try {
-            assertEquals(null, h3.join());
+            assertNull(h3.join());
             rs[3].assertValue(v1);
         } catch (CompletionException ok) {
             checkCompletedWithWrappedException(h3, ex);
@@ -2849,28 +2849,28 @@ public class CompletableFutureTest extends JSR166TestCase {
 
         // unspecified behavior - both source completions available
         try {
-            assertEquals(null, h0.join());
+            assertNull(h0.join());
             rs[0].assertInvoked();
         } catch (CompletionException ok) {
             checkCompletedWithWrappedException(h0, ex);
             rs[0].assertNotInvoked();
         }
         try {
-            assertEquals(null, h1.join());
+            assertNull(h1.join());
             rs[1].assertInvoked();
         } catch (CompletionException ok) {
             checkCompletedWithWrappedException(h1, ex);
             rs[1].assertNotInvoked();
         }
         try {
-            assertEquals(null, h2.join());
+            assertNull(h2.join());
             rs[2].assertInvoked();
         } catch (CompletionException ok) {
             checkCompletedWithWrappedException(h2, ex);
             rs[2].assertNotInvoked();
         }
         try {
-            assertEquals(null, h3.join());
+            assertNull(h3.join());
             rs[3].assertInvoked();
         } catch (CompletionException ok) {
             checkCompletedWithWrappedException(h3, ex);
diff --git a/jdk/test/java/util/concurrent/tck/ConcurrentHashMap8Test.java b/jdk/test/java/util/concurrent/tck/ConcurrentHashMap8Test.java
index 00f8dc6bb28..e0d9f81a7f1 100644
--- a/jdk/test/java/util/concurrent/tck/ConcurrentHashMap8Test.java
+++ b/jdk/test/java/util/concurrent/tck/ConcurrentHashMap8Test.java
@@ -237,8 +237,8 @@ public class ConcurrentHashMap8Test extends JSR166TestCase {
         Set set1 = map.keySet();
         Set set2 = map.keySet(true);
         set2.add(six);
-        assertTrue(((ConcurrentHashMap.KeySetView)set2).getMap() == map);
-        assertTrue(((ConcurrentHashMap.KeySetView)set1).getMap() == map);
+        assertSame(map, ((ConcurrentHashMap.KeySetView)set2).getMap());
+        assertSame(map, ((ConcurrentHashMap.KeySetView)set1).getMap());
         assertEquals(set2.size(), map.size());
         assertEquals(set1.size(), map.size());
         assertTrue((Boolean)map.get(six));
@@ -332,10 +332,10 @@ public class ConcurrentHashMap8Test extends JSR166TestCase {
         assertFalse(set.add(one));
         assertTrue(set.add(six));
         assertTrue(set.add(seven));
-        assertTrue(set.getMappedValue() == one);
-        assertTrue(map.get(one) != one);
-        assertTrue(map.get(six) == one);
-        assertTrue(map.get(seven) == one);
+        assertSame(one, set.getMappedValue());
+        assertNotSame(one, map.get(one));
+        assertSame(one, map.get(six));
+        assertSame(one, map.get(seven));
     }
 
     void checkSpliteratorCharacteristics(Spliterator<?> sp,
diff --git a/jdk/test/java/util/concurrent/tck/ConcurrentHashMapTest.java b/jdk/test/java/util/concurrent/tck/ConcurrentHashMapTest.java
index 1485d2c4dca..729a6e3d146 100644
--- a/jdk/test/java/util/concurrent/tck/ConcurrentHashMapTest.java
+++ b/jdk/test/java/util/concurrent/tck/ConcurrentHashMapTest.java
@@ -43,8 +43,6 @@ import java.util.Map;
 import java.util.Random;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
 
 import junit.framework.Test;
 import junit.framework.TestSuite;
@@ -148,7 +146,7 @@ public class ConcurrentHashMapTest extends JSR166TestCase {
         ConcurrentHashMap<BI, Boolean> m =
             new ConcurrentHashMap<BI, Boolean>();
         for (int i = 0; i < size; i++) {
-            assertTrue(m.put(new CI(i), true) == null);
+            assertNull(m.put(new CI(i), true));
         }
         for (int i = 0; i < size; i++) {
             assertTrue(m.containsKey(new CI(i)));
@@ -169,7 +167,7 @@ public class ConcurrentHashMapTest extends JSR166TestCase {
             BS bs = new BS(String.valueOf(i));
             LexicographicList<BI> bis = new LexicographicList<BI>(bi);
             LexicographicList<BS> bss = new LexicographicList<BS>(bs);
-            assertTrue(m.putIfAbsent(bis, true) == null);
+            assertNull(m.putIfAbsent(bis, true));
             assertTrue(m.containsKey(bis));
             if (m.putIfAbsent(bss, true) == null)
                 assertTrue(m.containsKey(bss));
diff --git a/jdk/test/java/util/concurrent/tck/ConcurrentLinkedDequeTest.java b/jdk/test/java/util/concurrent/tck/ConcurrentLinkedDequeTest.java
index aac0bb73910..8a8ffeb6ff9 100644
--- a/jdk/test/java/util/concurrent/tck/ConcurrentLinkedDequeTest.java
+++ b/jdk/test/java/util/concurrent/tck/ConcurrentLinkedDequeTest.java
@@ -43,7 +43,6 @@ import java.util.Random;
 import java.util.concurrent.ConcurrentLinkedDeque;
 
 import junit.framework.Test;
-import junit.framework.TestSuite;
 
 public class ConcurrentLinkedDequeTest extends JSR166TestCase {
 
@@ -67,7 +66,7 @@ public class ConcurrentLinkedDequeTest extends JSR166TestCase {
      * Returns a new deque of given size containing consecutive
      * Integers 0 ... n - 1.
      */
-    private ConcurrentLinkedDeque<Integer> populatedDeque(int n) {
+    private static ConcurrentLinkedDeque<Integer> populatedDeque(int n) {
         ConcurrentLinkedDeque<Integer> q = new ConcurrentLinkedDeque<>();
         assertTrue(q.isEmpty());
         for (int i = 0; i < n; ++i)
diff --git a/jdk/test/java/util/concurrent/tck/ConcurrentLinkedQueueTest.java b/jdk/test/java/util/concurrent/tck/ConcurrentLinkedQueueTest.java
index 57689cce48d..ee6827a660f 100644
--- a/jdk/test/java/util/concurrent/tck/ConcurrentLinkedQueueTest.java
+++ b/jdk/test/java/util/concurrent/tck/ConcurrentLinkedQueueTest.java
@@ -41,7 +41,6 @@ import java.util.Queue;
 import java.util.concurrent.ConcurrentLinkedQueue;
 
 import junit.framework.Test;
-import junit.framework.TestSuite;
 
 public class ConcurrentLinkedQueueTest extends JSR166TestCase {
 
@@ -65,7 +64,7 @@ public class ConcurrentLinkedQueueTest extends JSR166TestCase {
      * Returns a new queue of given size containing consecutive
      * Integers 0 ... n - 1.
      */
-    private ConcurrentLinkedQueue<Integer> populatedQueue(int n) {
+    private static ConcurrentLinkedQueue<Integer> populatedQueue(int n) {
         ConcurrentLinkedQueue<Integer> q = new ConcurrentLinkedQueue<>();
         assertTrue(q.isEmpty());
         for (int i = 0; i < n; ++i)
diff --git a/jdk/test/java/util/concurrent/tck/ConcurrentSkipListSetTest.java b/jdk/test/java/util/concurrent/tck/ConcurrentSkipListSetTest.java
index ae91219f622..cb28b6ae0e7 100644
--- a/jdk/test/java/util/concurrent/tck/ConcurrentSkipListSetTest.java
+++ b/jdk/test/java/util/concurrent/tck/ConcurrentSkipListSetTest.java
@@ -64,7 +64,7 @@ public class ConcurrentSkipListSetTest extends JSR166TestCase {
      * Returns a new set of given size containing consecutive
      * Integers 0 ... n - 1.
      */
-    private ConcurrentSkipListSet<Integer> populatedSet(int n) {
+    private static ConcurrentSkipListSet<Integer> populatedSet(int n) {
         ConcurrentSkipListSet<Integer> q =
             new ConcurrentSkipListSet<Integer>();
         assertTrue(q.isEmpty());
@@ -80,7 +80,7 @@ public class ConcurrentSkipListSetTest extends JSR166TestCase {
     /**
      * Returns a new set of first 5 ints.
      */
-    private ConcurrentSkipListSet set5() {
+    private static ConcurrentSkipListSet set5() {
         ConcurrentSkipListSet q = new ConcurrentSkipListSet();
         assertTrue(q.isEmpty());
         q.add(one);
@@ -229,7 +229,7 @@ public class ConcurrentSkipListSetTest extends JSR166TestCase {
         } catch (ClassCastException success) {
             assertTrue(q.size() < 2);
             for (int i = 0, size = q.size(); i < size; i++)
-                assertTrue(q.pollFirst().getClass() == Object.class);
+                assertSame(Object.class, q.pollFirst().getClass());
             assertNull(q.pollFirst());
             assertTrue(q.isEmpty());
             assertEquals(0, q.size());
diff --git a/jdk/test/java/util/concurrent/tck/ConcurrentSkipListSubSetTest.java b/jdk/test/java/util/concurrent/tck/ConcurrentSkipListSubSetTest.java
index 4b299e74b83..19d34cc01e1 100644
--- a/jdk/test/java/util/concurrent/tck/ConcurrentSkipListSubSetTest.java
+++ b/jdk/test/java/util/concurrent/tck/ConcurrentSkipListSubSetTest.java
@@ -59,7 +59,7 @@ public class ConcurrentSkipListSubSetTest extends JSR166TestCase {
      * Returns a new set of given size containing consecutive
      * Integers 0 ... n - 1.
      */
-    private NavigableSet<Integer> populatedSet(int n) {
+    private static NavigableSet<Integer> populatedSet(int n) {
         ConcurrentSkipListSet<Integer> q =
             new ConcurrentSkipListSet<Integer>();
         assertTrue(q.isEmpty());
@@ -79,7 +79,7 @@ public class ConcurrentSkipListSubSetTest extends JSR166TestCase {
     /**
      * Returns a new set of first 5 ints.
      */
-    private NavigableSet set5() {
+    private static NavigableSet set5() {
         ConcurrentSkipListSet q = new ConcurrentSkipListSet();
         assertTrue(q.isEmpty());
         q.add(one);
@@ -97,7 +97,7 @@ public class ConcurrentSkipListSubSetTest extends JSR166TestCase {
     /**
      * Returns a new set of first 5 negative ints.
      */
-    private NavigableSet dset5() {
+    private static NavigableSet dset5() {
         ConcurrentSkipListSet q = new ConcurrentSkipListSet();
         assertTrue(q.isEmpty());
         q.add(m1);
diff --git a/jdk/test/java/util/concurrent/tck/CopyOnWriteArrayListTest.java b/jdk/test/java/util/concurrent/tck/CopyOnWriteArrayListTest.java
index 329010b308b..2b13e130701 100644
--- a/jdk/test/java/util/concurrent/tck/CopyOnWriteArrayListTest.java
+++ b/jdk/test/java/util/concurrent/tck/CopyOnWriteArrayListTest.java
@@ -44,7 +44,6 @@ import java.util.NoSuchElementException;
 import java.util.concurrent.CopyOnWriteArrayList;
 
 import junit.framework.Test;
-import junit.framework.TestSuite;
 
 public class CopyOnWriteArrayListTest extends JSR166TestCase {
 
diff --git a/jdk/test/java/util/concurrent/tck/CountedCompleter8Test.java b/jdk/test/java/util/concurrent/tck/CountedCompleter8Test.java
index eb23564ed77..77e800c23b3 100644
--- a/jdk/test/java/util/concurrent/tck/CountedCompleter8Test.java
+++ b/jdk/test/java/util/concurrent/tck/CountedCompleter8Test.java
@@ -32,9 +32,6 @@
  * http://creativecommons.org/publicdomain/zero/1.0/
  */
 
-import static java.util.concurrent.TimeUnit.MILLISECONDS;
-import static java.util.concurrent.TimeUnit.SECONDS;
-
 import java.util.concurrent.CountedCompleter;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.atomic.AtomicInteger;
diff --git a/jdk/test/java/util/concurrent/tck/CountedCompleterTest.java b/jdk/test/java/util/concurrent/tck/CountedCompleterTest.java
index 3113b57a563..66e5bd61761 100644
--- a/jdk/test/java/util/concurrent/tck/CountedCompleterTest.java
+++ b/jdk/test/java/util/concurrent/tck/CountedCompleterTest.java
@@ -40,7 +40,6 @@ import java.util.concurrent.CountedCompleter;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ForkJoinPool;
 import java.util.concurrent.ForkJoinTask;
-import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
diff --git a/jdk/test/java/util/concurrent/tck/ExchangerTest.java b/jdk/test/java/util/concurrent/tck/ExchangerTest.java
index ba6c5443623..36eacc7891e 100644
--- a/jdk/test/java/util/concurrent/tck/ExchangerTest.java
+++ b/jdk/test/java/util/concurrent/tck/ExchangerTest.java
@@ -160,12 +160,12 @@ public class ExchangerTest extends JSR166TestCase {
             public void realRun() throws InterruptedException {
                 assertSame(one, e.exchange(two));
                 exchanged.countDown();
-                interrupted.await();
+                await(interrupted);
                 assertSame(three, e.exchange(one));
             }});
         Thread t3 = newStartedThread(new CheckedRunnable() {
             public void realRun() throws InterruptedException {
-                interrupted.await();
+                await(interrupted);
                 assertSame(one, e.exchange(three));
             }});
 
diff --git a/jdk/test/java/util/concurrent/tck/ExecutorCompletionService9Test.java b/jdk/test/java/util/concurrent/tck/ExecutorCompletionService9Test.java
index 4ca78a09a49..92e92478cbc 100644
--- a/jdk/test/java/util/concurrent/tck/ExecutorCompletionService9Test.java
+++ b/jdk/test/java/util/concurrent/tck/ExecutorCompletionService9Test.java
@@ -37,7 +37,6 @@ import java.util.Collection;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Set;
-import java.util.HashSet;
 import java.util.concurrent.Callable;
 import java.util.concurrent.CompletionService;
 import java.util.concurrent.ExecutionException;
diff --git a/jdk/test/java/util/concurrent/tck/ExecutorCompletionServiceTest.java b/jdk/test/java/util/concurrent/tck/ExecutorCompletionServiceTest.java
index 0ab6084b978..9b7251e6865 100644
--- a/jdk/test/java/util/concurrent/tck/ExecutorCompletionServiceTest.java
+++ b/jdk/test/java/util/concurrent/tck/ExecutorCompletionServiceTest.java
@@ -172,7 +172,7 @@ public class ExecutorCompletionServiceTest extends JSR166TestCase {
         CompletionService cs = new ExecutorCompletionService(cachedThreadPool);
         final CountDownLatch proceed = new CountDownLatch(1);
         cs.submit(new Callable() { public String call() throws Exception {
-            proceed.await();
+            await(proceed);
             return TEST_STRING;
         }});
         assertNull(cs.poll());
diff --git a/jdk/test/java/util/concurrent/tck/ExecutorsTest.java b/jdk/test/java/util/concurrent/tck/ExecutorsTest.java
index 441a52a5922..90764242502 100644
--- a/jdk/test/java/util/concurrent/tck/ExecutorsTest.java
+++ b/jdk/test/java/util/concurrent/tck/ExecutorsTest.java
@@ -333,16 +333,12 @@ public class ExecutorsTest extends JSR166TestCase {
             public void realRun() {
                 try {
                     Thread current = Thread.currentThread();
-                    assertTrue(!current.isDaemon());
+                    assertFalse(current.isDaemon());
                     assertTrue(current.getPriority() <= Thread.NORM_PRIORITY);
-                    ThreadGroup g = current.getThreadGroup();
                     SecurityManager s = System.getSecurityManager();
-                    if (s != null)
-                        assertTrue(g == s.getThreadGroup());
-                    else
-                        assertTrue(g == egroup);
-                    String name = current.getName();
-                    assertTrue(name.endsWith("thread-1"));
+                    assertSame(current.getThreadGroup(),
+                               (s == null) ? egroup : s.getThreadGroup());
+                    assertTrue(current.getName().endsWith("thread-1"));
                 } catch (SecurityException ok) {
                     // Also pass if not allowed to change setting
                 }
@@ -370,16 +366,12 @@ public class ExecutorsTest extends JSR166TestCase {
                 Runnable r = new CheckedRunnable() {
                     public void realRun() {
                         Thread current = Thread.currentThread();
-                        assertTrue(!current.isDaemon());
+                        assertFalse(current.isDaemon());
                         assertTrue(current.getPriority() <= Thread.NORM_PRIORITY);
-                        ThreadGroup g = current.getThreadGroup();
                         SecurityManager s = System.getSecurityManager();
-                        if (s != null)
-                            assertTrue(g == s.getThreadGroup());
-                        else
-                            assertTrue(g == egroup);
-                        String name = current.getName();
-                        assertTrue(name.endsWith("thread-1"));
+                        assertSame(current.getThreadGroup(),
+                                   (s == null) ? egroup : s.getThreadGroup());
+                        assertTrue(current.getName().endsWith("thread-1"));
                         assertSame(thisccl, current.getContextClassLoader());
                         assertEquals(thisacc, AccessController.getContext());
                         done.countDown();
diff --git a/jdk/test/java/util/concurrent/tck/ForkJoinPool8Test.java b/jdk/test/java/util/concurrent/tck/ForkJoinPool8Test.java
index b0fea9a0bfe..f24de8828dc 100644
--- a/jdk/test/java/util/concurrent/tck/ForkJoinPool8Test.java
+++ b/jdk/test/java/util/concurrent/tck/ForkJoinPool8Test.java
@@ -206,7 +206,7 @@ public class ForkJoinPool8Test extends JSR166TestCase {
         public FJException(Throwable cause) { super(cause); }
     }
 
-    // A simple recursive action for testing
+    /** A simple recursive action for testing. */
     final class FibAction extends CheckedRecursiveAction {
         final int number;
         int result;
@@ -224,7 +224,7 @@ public class ForkJoinPool8Test extends JSR166TestCase {
         }
     }
 
-    // A recursive action failing in base case
+    /** A recursive action failing in base case. */
     static final class FailingFibAction extends RecursiveAction {
         final int number;
         int result;
@@ -932,7 +932,7 @@ public class ForkJoinPool8Test extends JSR166TestCase {
         }
     }
 
-    // Version of CCF with forced failure in left completions
+    /** Version of CCF with forced failure in left completions. */
     abstract static class FailingCCF extends CountedCompleter {
         int number;
         int rnumber;
diff --git a/jdk/test/java/util/concurrent/tck/ForkJoinPool9Test.java b/jdk/test/java/util/concurrent/tck/ForkJoinPool9Test.java
index 8a87e473a6f..b4153481d61 100644
--- a/jdk/test/java/util/concurrent/tck/ForkJoinPool9Test.java
+++ b/jdk/test/java/util/concurrent/tck/ForkJoinPool9Test.java
@@ -32,8 +32,6 @@
  * http://creativecommons.org/publicdomain/zero/1.0/
  */
 
-import static java.util.concurrent.TimeUnit.MILLISECONDS;
-
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.VarHandle;
 import java.util.concurrent.CountDownLatch;
@@ -93,7 +91,7 @@ public class ForkJoinPool9Test extends JSR166TestCase {
         Future<?> f = ForkJoinPool.commonPool().submit(runInCommonPool);
         // Ensure runInCommonPool is truly running in the common pool,
         // by giving this thread no opportunity to "help" on get().
-        assertTrue(taskStarted.await(LONG_DELAY_MS, MILLISECONDS));
+        await(taskStarted);
         assertNull(f.get());
     }
 
diff --git a/jdk/test/java/util/concurrent/tck/ForkJoinPoolTest.java b/jdk/test/java/util/concurrent/tck/ForkJoinPoolTest.java
index bf5a3652f09..766e35081e3 100644
--- a/jdk/test/java/util/concurrent/tck/ForkJoinPoolTest.java
+++ b/jdk/test/java/util/concurrent/tck/ForkJoinPoolTest.java
@@ -244,7 +244,7 @@ public class ForkJoinPoolTest extends JSR166TestCase {
                     taskStarted.countDown();
                     assertEquals(1, p.getPoolSize());
                     assertEquals(1, p.getActiveThreadCount());
-                    done.await();
+                    await(done);
                 }};
             Future<?> future = p.submit(task);
             await(taskStarted);
diff --git a/jdk/test/java/util/concurrent/tck/ForkJoinTask8Test.java b/jdk/test/java/util/concurrent/tck/ForkJoinTask8Test.java
index c1063da31aa..6415111510c 100644
--- a/jdk/test/java/util/concurrent/tck/ForkJoinTask8Test.java
+++ b/jdk/test/java/util/concurrent/tck/ForkJoinTask8Test.java
@@ -127,7 +127,8 @@ public class ForkJoinTask8Test extends JSR166TestCase {
         assertNull(a.getException());
         assertNull(a.getRawResult());
         if (a instanceof BinaryAsyncAction)
-            assertTrue(((BinaryAsyncAction)a).getForkJoinTaskTag() == INITIAL_STATE);
+            assertEquals(INITIAL_STATE,
+                         ((BinaryAsyncAction)a).getForkJoinTaskTag());
 
         try {
             a.get(0L, SECONDS);
@@ -148,7 +149,8 @@ public class ForkJoinTask8Test extends JSR166TestCase {
         assertNull(a.getException());
         assertSame(expected, a.getRawResult());
         if (a instanceof BinaryAsyncAction)
-            assertTrue(((BinaryAsyncAction)a).getForkJoinTaskTag() == COMPLETE_STATE);
+            assertEquals(COMPLETE_STATE,
+                         ((BinaryAsyncAction)a).getForkJoinTaskTag());
 
         {
             Thread.currentThread().interrupt();
diff --git a/jdk/test/java/util/concurrent/tck/JSR166TestCase.java b/jdk/test/java/util/concurrent/tck/JSR166TestCase.java
index 1037eb8f3e7..9625be26fea 100644
--- a/jdk/test/java/util/concurrent/tck/JSR166TestCase.java
+++ b/jdk/test/java/util/concurrent/tck/JSR166TestCase.java
@@ -26,8 +26,9 @@
  * However, the following notice accompanied the original version of this
  * file:
  *
- * Written by Doug Lea with assistance from members of JCP JSR-166
- * Expert Group and released to the public domain, as explained at
+ * Written by Doug Lea and Martin Buchholz with assistance from
+ * members of JCP JSR-166 Expert Group and released to the public
+ * domain, as explained at
  * http://creativecommons.org/publicdomain/zero/1.0/
  * Other contributors include Andrew Wright, Jeffrey Hayes,
  * Pat Fisher, Mike Judd.
@@ -35,32 +36,33 @@
 
 /*
  * @test
- * @summary JSR-166 tck tests (conformance testing mode)
+ * @summary JSR-166 tck tests, in a number of variations.
+ *          The first is the conformance testing variant,
+ *          while others also test implementation details.
  * @build *
  * @modules java.management
  * @run junit/othervm/timeout=1000 JSR166TestCase
- */
-
-/*
- * @test
- * @summary JSR-166 tck tests (whitebox tests allowed)
- * @build *
- * @modules java.base/java.util.concurrent:open
- *          java.base/java.lang:open
- *          java.management
  * @run junit/othervm/timeout=1000
+ *      --add-opens java.base/java.util.concurrent=ALL-UNNAMED
+ *      --add-opens java.base/java.lang=ALL-UNNAMED
  *      -Djsr166.testImplementationDetails=true
  *      JSR166TestCase
  * @run junit/othervm/timeout=1000
+ *      --add-opens java.base/java.util.concurrent=ALL-UNNAMED
+ *      --add-opens java.base/java.lang=ALL-UNNAMED
  *      -Djsr166.testImplementationDetails=true
  *      -Djava.util.concurrent.ForkJoinPool.common.parallelism=0
  *      JSR166TestCase
  * @run junit/othervm/timeout=1000
+ *      --add-opens java.base/java.util.concurrent=ALL-UNNAMED
+ *      --add-opens java.base/java.lang=ALL-UNNAMED
  *      -Djsr166.testImplementationDetails=true
  *      -Djava.util.concurrent.ForkJoinPool.common.parallelism=1
  *      -Djava.util.secureRandomSeed=true
  *      JSR166TestCase
  * @run junit/othervm/timeout=1000/policy=tck.policy
+ *      --add-opens java.base/java.util.concurrent=ALL-UNNAMED
+ *      --add-opens java.base/java.lang=ALL-UNNAMED
  *      -Djsr166.testImplementationDetails=true
  *      JSR166TestCase
  */
@@ -79,8 +81,6 @@ import java.lang.management.ThreadMXBean;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
-import java.nio.file.Files;
-import java.nio.file.Paths;
 import java.security.CodeSource;
 import java.security.Permission;
 import java.security.PermissionCollection;
@@ -118,7 +118,6 @@ import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
-import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import junit.framework.AssertionFailedError;
@@ -328,9 +327,11 @@ public class JSR166TestCase extends TestCase {
 
 //     public static String cpuModel() {
 //         try {
-//             Matcher matcher = Pattern.compile("model name\\s*: (.*)")
+//             java.util.regex.Matcher matcher
+//               = Pattern.compile("model name\\s*: (.*)")
 //                 .matcher(new String(
-//                      Files.readAllBytes(Paths.get("/proc/cpuinfo")), "UTF-8"));
+//                     java.nio.file.Files.readAllBytes(
+//                         java.nio.file.Paths.get("/proc/cpuinfo")), "UTF-8"));
 //             matcher.find();
 //             return matcher.group(1);
 //         } catch (Exception ex) { return null; }
diff --git a/jdk/test/java/util/concurrent/tck/LinkedBlockingDeque8Test.java b/jdk/test/java/util/concurrent/tck/LinkedBlockingDeque8Test.java
index 44dcedc0f01..cdcc7a27334 100644
--- a/jdk/test/java/util/concurrent/tck/LinkedBlockingDeque8Test.java
+++ b/jdk/test/java/util/concurrent/tck/LinkedBlockingDeque8Test.java
@@ -36,7 +36,6 @@ import java.util.concurrent.LinkedBlockingDeque;
 import java.util.Spliterator;
 
 import junit.framework.Test;
-import junit.framework.TestSuite;
 
 public class LinkedBlockingDeque8Test extends JSR166TestCase {
     public static void main(String[] args) {
diff --git a/jdk/test/java/util/concurrent/tck/LinkedBlockingDequeTest.java b/jdk/test/java/util/concurrent/tck/LinkedBlockingDequeTest.java
index 2559fdffe9d..00fbcc9734b 100644
--- a/jdk/test/java/util/concurrent/tck/LinkedBlockingDequeTest.java
+++ b/jdk/test/java/util/concurrent/tck/LinkedBlockingDequeTest.java
@@ -85,7 +85,7 @@ public class LinkedBlockingDequeTest extends JSR166TestCase {
      * Returns a new deque of given size containing consecutive
      * Integers 0 ... n - 1.
      */
-    private LinkedBlockingDeque<Integer> populatedDeque(int n) {
+    private static LinkedBlockingDeque<Integer> populatedDeque(int n) {
         LinkedBlockingDeque<Integer> q =
             new LinkedBlockingDeque<Integer>(n);
         assertTrue(q.isEmpty());
@@ -801,7 +801,7 @@ public class LinkedBlockingDequeTest extends JSR166TestCase {
                 }
             }});
 
-        aboutToWait.await();
+        await(aboutToWait);
         waitForThreadToEnterWaitState(t);
         t.interrupt();
         awaitTermination(t);
diff --git a/jdk/test/java/util/concurrent/tck/LinkedBlockingQueue8Test.java b/jdk/test/java/util/concurrent/tck/LinkedBlockingQueue8Test.java
index 9900c33da70..2c3e498aeaa 100644
--- a/jdk/test/java/util/concurrent/tck/LinkedBlockingQueue8Test.java
+++ b/jdk/test/java/util/concurrent/tck/LinkedBlockingQueue8Test.java
@@ -36,7 +36,6 @@ import java.util.concurrent.LinkedBlockingQueue;
 import java.util.Spliterator;
 
 import junit.framework.Test;
-import junit.framework.TestSuite;
 
 public class LinkedBlockingQueue8Test extends JSR166TestCase {
     public static void main(String[] args) {
diff --git a/jdk/test/java/util/concurrent/tck/LinkedBlockingQueueTest.java b/jdk/test/java/util/concurrent/tck/LinkedBlockingQueueTest.java
index 153cbce667a..cdccb75ed87 100644
--- a/jdk/test/java/util/concurrent/tck/LinkedBlockingQueueTest.java
+++ b/jdk/test/java/util/concurrent/tck/LinkedBlockingQueueTest.java
@@ -85,7 +85,7 @@ public class LinkedBlockingQueueTest extends JSR166TestCase {
      * Returns a new queue of given size containing consecutive
      * Integers 0 ... n - 1.
      */
-    private LinkedBlockingQueue<Integer> populatedQueue(int n) {
+    private static LinkedBlockingQueue<Integer> populatedQueue(int n) {
         LinkedBlockingQueue<Integer> q =
             new LinkedBlockingQueue<Integer>(n);
         assertTrue(q.isEmpty());
diff --git a/jdk/test/java/util/concurrent/tck/LinkedListTest.java b/jdk/test/java/util/concurrent/tck/LinkedListTest.java
index 08a2ddd9dab..66dd8c02c7a 100644
--- a/jdk/test/java/util/concurrent/tck/LinkedListTest.java
+++ b/jdk/test/java/util/concurrent/tck/LinkedListTest.java
@@ -40,7 +40,6 @@ import java.util.LinkedList;
 import java.util.NoSuchElementException;
 
 import junit.framework.Test;
-import junit.framework.TestSuite;
 
 public class LinkedListTest extends JSR166TestCase {
     public static void main(String[] args) {
@@ -70,7 +69,7 @@ public class LinkedListTest extends JSR166TestCase {
      * Returns a new queue of given size containing consecutive
      * Integers 0 ... n - 1.
      */
-    private LinkedList<Integer> populatedQueue(int n) {
+    private static LinkedList<Integer> populatedQueue(int n) {
         LinkedList<Integer> q = new LinkedList<>();
         assertTrue(q.isEmpty());
         for (int i = 0; i < n; ++i)
diff --git a/jdk/test/java/util/concurrent/tck/LinkedTransferQueueTest.java b/jdk/test/java/util/concurrent/tck/LinkedTransferQueueTest.java
index 6a22b0e20a9..7f38351a30a 100644
--- a/jdk/test/java/util/concurrent/tck/LinkedTransferQueueTest.java
+++ b/jdk/test/java/util/concurrent/tck/LinkedTransferQueueTest.java
@@ -321,7 +321,7 @@ public class LinkedTransferQueueTest extends JSR166TestCase {
                 assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
             }});
 
-        aboutToWait.await();
+        await(aboutToWait);
         waitForThreadToEnterWaitState(t);
         t.interrupt();
         awaitTermination(t);
@@ -826,7 +826,7 @@ public class LinkedTransferQueueTest extends JSR166TestCase {
         Thread first = newStartedThread(new CheckedRunnable() {
             public void realRun() throws InterruptedException {
                 q.transfer(four);
-                assertTrue(!q.contains(four));
+                assertFalse(q.contains(four));
                 assertEquals(1, q.size());
             }});
 
diff --git a/jdk/test/java/util/concurrent/tck/PriorityBlockingQueueTest.java b/jdk/test/java/util/concurrent/tck/PriorityBlockingQueueTest.java
index 088c389b2cc..aa826b80f1b 100644
--- a/jdk/test/java/util/concurrent/tck/PriorityBlockingQueueTest.java
+++ b/jdk/test/java/util/concurrent/tck/PriorityBlockingQueueTest.java
@@ -93,7 +93,7 @@ public class PriorityBlockingQueueTest extends JSR166TestCase {
      * Returns a new queue of given size containing consecutive
      * Integers 0 ... n - 1.
      */
-    private PriorityBlockingQueue<Integer> populatedQueue(int n) {
+    private static PriorityBlockingQueue<Integer> populatedQueue(int n) {
         PriorityBlockingQueue<Integer> q =
             new PriorityBlockingQueue<Integer>(n);
         assertTrue(q.isEmpty());
@@ -445,7 +445,7 @@ public class PriorityBlockingQueueTest extends JSR166TestCase {
                 }
             }});
 
-        aboutToWait.await();
+        await(aboutToWait);
         waitForThreadToEnterWaitState(t);
         t.interrupt();
         awaitTermination(t);
diff --git a/jdk/test/java/util/concurrent/tck/PriorityQueueTest.java b/jdk/test/java/util/concurrent/tck/PriorityQueueTest.java
index c1564730cdf..1c3984dd197 100644
--- a/jdk/test/java/util/concurrent/tck/PriorityQueueTest.java
+++ b/jdk/test/java/util/concurrent/tck/PriorityQueueTest.java
@@ -42,7 +42,6 @@ import java.util.PriorityQueue;
 import java.util.Queue;
 
 import junit.framework.Test;
-import junit.framework.TestSuite;
 
 public class PriorityQueueTest extends JSR166TestCase {
     public static void main(String[] args) {
@@ -70,7 +69,7 @@ public class PriorityQueueTest extends JSR166TestCase {
      * Returns a new queue of given size containing consecutive
      * Integers 0 ... n - 1.
      */
-    private PriorityQueue<Integer> populatedQueue(int n) {
+    private static PriorityQueue<Integer> populatedQueue(int n) {
         PriorityQueue<Integer> q = new PriorityQueue<>(n);
         assertTrue(q.isEmpty());
         for (int i = n - 1; i >= 0; i -= 2)
diff --git a/jdk/test/java/util/concurrent/tck/RecursiveActionTest.java b/jdk/test/java/util/concurrent/tck/RecursiveActionTest.java
index 01bd92770b7..132b8dad7b0 100644
--- a/jdk/test/java/util/concurrent/tck/RecursiveActionTest.java
+++ b/jdk/test/java/util/concurrent/tck/RecursiveActionTest.java
@@ -195,7 +195,7 @@ public class RecursiveActionTest extends JSR166TestCase {
         public FJException(Throwable cause) { super(cause); }
     }
 
-    // A simple recursive action for testing
+    /** A simple recursive action for testing. */
     final class FibAction extends CheckedRecursiveAction {
         final int number;
         int result;
@@ -213,7 +213,7 @@ public class RecursiveActionTest extends JSR166TestCase {
         }
     }
 
-    // A recursive action failing in base case
+    /** A recursive action failing in base case. */
     static final class FailingFibAction extends RecursiveAction {
         final int number;
         int result;
diff --git a/jdk/test/java/util/concurrent/tck/RecursiveTaskTest.java b/jdk/test/java/util/concurrent/tck/RecursiveTaskTest.java
index ce13daa8e7b..49723adcff7 100644
--- a/jdk/test/java/util/concurrent/tck/RecursiveTaskTest.java
+++ b/jdk/test/java/util/concurrent/tck/RecursiveTaskTest.java
@@ -210,10 +210,10 @@ public class RecursiveTaskTest extends JSR166TestCase {
         public FJException() { super(); }
     }
 
-    // An invalid return value for Fib
+    /** An invalid return value for Fib. */
     static final Integer NoResult = Integer.valueOf(-17);
 
-    // A simple recursive task for testing
+    /** A simple recursive task for testing. */
     final class FibTask extends CheckedRecursiveTask<Integer> {
         final int number;
         FibTask(int n) { number = n; }
@@ -231,7 +231,7 @@ public class RecursiveTaskTest extends JSR166TestCase {
         }
     }
 
-    // A recursive action failing in base case
+    /** A recursive action failing in base case. */
     final class FailingFibTask extends RecursiveTask<Integer> {
         final int number;
         int result;
diff --git a/jdk/test/java/util/concurrent/tck/StampedLockTest.java b/jdk/test/java/util/concurrent/tck/StampedLockTest.java
index 65ef48d046b..5f44312c88c 100644
--- a/jdk/test/java/util/concurrent/tck/StampedLockTest.java
+++ b/jdk/test/java/util/concurrent/tck/StampedLockTest.java
@@ -518,7 +518,7 @@ public class StampedLockTest extends JSR166TestCase {
                 lock.unlockWrite(s);
             }});
 
-        aboutToLock.await();
+        await(aboutToLock);
         waitForThreadToEnterWaitState(t);
         assertFalse(lock.isWriteLocked());
         assertTrue(lock.isReadLocked());
@@ -777,7 +777,7 @@ public class StampedLockTest extends JSR166TestCase {
                 lock.writeLockInterruptibly();
             }});
 
-        locked.await();
+        await(locked);
         assertFalse(lock.validate(p));
         assertEquals(0L, lock.tryOptimisticRead());
         waitForThreadToEnterWaitState(t);
diff --git a/jdk/test/java/util/concurrent/tck/SubmissionPublisherTest.java b/jdk/test/java/util/concurrent/tck/SubmissionPublisherTest.java
index 102d1b5e3ef..ecd472f2cbe 100644
--- a/jdk/test/java/util/concurrent/tck/SubmissionPublisherTest.java
+++ b/jdk/test/java/util/concurrent/tck/SubmissionPublisherTest.java
@@ -519,7 +519,7 @@ public class SubmissionPublisherTest extends JSR166TestCase {
         s1.request = false;
         p.subscribe(s1);
         s1.awaitSubscribe();
-        assertTrue(p.estimateMinimumDemand() == 0);
+        assertEquals(0, p.estimateMinimumDemand());
         TestSubscriber s2 = new TestSubscriber();
         p.subscribe(s2);
         p.submit(1);
diff --git a/jdk/test/java/util/concurrent/tck/SynchronousQueueTest.java b/jdk/test/java/util/concurrent/tck/SynchronousQueueTest.java
index 345ac9c7305..afa4f5c026c 100644
--- a/jdk/test/java/util/concurrent/tck/SynchronousQueueTest.java
+++ b/jdk/test/java/util/concurrent/tck/SynchronousQueueTest.java
@@ -596,7 +596,7 @@ public class SynchronousQueueTest extends JSR166TestCase {
                 fail("timed out");
             Thread.yield();
         }
-        assertTrue(l.size() == 1);
+        assertEquals(1, l.size());
         assertSame(one, l.get(0));
         awaitTermination(t);
     }
diff --git a/jdk/test/java/util/concurrent/tck/ThreadPoolExecutorSubclassTest.java b/jdk/test/java/util/concurrent/tck/ThreadPoolExecutorSubclassTest.java
index 38862ceee5d..90065c65790 100644
--- a/jdk/test/java/util/concurrent/tck/ThreadPoolExecutorSubclassTest.java
+++ b/jdk/test/java/util/concurrent/tck/ThreadPoolExecutorSubclassTest.java
@@ -265,7 +265,7 @@ public class ThreadPoolExecutorSubclassTest extends JSR166TestCase {
             final Runnable task = new CheckedRunnable() {
                 public void realRun() { done.countDown(); }};
             p.execute(task);
-            assertTrue(done.await(LONG_DELAY_MS, MILLISECONDS));
+            await(done);
         }
     }
 
@@ -359,13 +359,13 @@ public class ThreadPoolExecutorSubclassTest extends JSR166TestCase {
                 public void realRun() throws InterruptedException {
                     threadStarted.countDown();
                     assertEquals(0, p.getCompletedTaskCount());
-                    threadProceed.await();
+                    await(threadProceed);
                     threadDone.countDown();
                 }});
             await(threadStarted);
             assertEquals(0, p.getCompletedTaskCount());
             threadProceed.countDown();
-            threadDone.await();
+            await(threadDone);
             long startTime = System.nanoTime();
             while (p.getCompletedTaskCount() != 1) {
                 if (millisElapsedSince(startTime) > LONG_DELAY_MS)
@@ -1953,7 +1953,7 @@ public class ThreadPoolExecutorSubclassTest extends JSR166TestCase {
                     public void realRun() {
                         done.countDown();
                     }});
-            assertTrue(done.await(LONG_DELAY_MS, MILLISECONDS));
+            await(done);
         }
     }
 
diff --git a/jdk/test/java/util/concurrent/tck/ThreadPoolExecutorTest.java b/jdk/test/java/util/concurrent/tck/ThreadPoolExecutorTest.java
index cf0b0971270..9cbb98562f6 100644
--- a/jdk/test/java/util/concurrent/tck/ThreadPoolExecutorTest.java
+++ b/jdk/test/java/util/concurrent/tck/ThreadPoolExecutorTest.java
@@ -45,7 +45,6 @@ import java.util.concurrent.Callable;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutionException;
-import java.util.concurrent.Executors;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Future;
 import java.util.concurrent.FutureTask;
@@ -118,7 +117,7 @@ public class ThreadPoolExecutorTest extends JSR166TestCase {
             final Runnable task = new CheckedRunnable() {
                 public void realRun() { done.countDown(); }};
             p.execute(task);
-            assertTrue(done.await(LONG_DELAY_MS, MILLISECONDS));
+            await(done);
         }
     }
 
@@ -212,13 +211,13 @@ public class ThreadPoolExecutorTest extends JSR166TestCase {
                 public void realRun() throws InterruptedException {
                     threadStarted.countDown();
                     assertEquals(0, p.getCompletedTaskCount());
-                    threadProceed.await();
+                    await(threadProceed);
                     threadDone.countDown();
                 }});
             await(threadStarted);
             assertEquals(0, p.getCompletedTaskCount());
             threadProceed.countDown();
-            threadDone.await();
+            await(threadDone);
             long startTime = System.nanoTime();
             while (p.getCompletedTaskCount() != 1) {
                 if (millisElapsedSince(startTime) > LONG_DELAY_MS)
@@ -301,6 +300,20 @@ public class ThreadPoolExecutorTest extends JSR166TestCase {
         }
     }
 
+    /**
+     * The default rejected execution handler is AbortPolicy.
+     */
+    public void testDefaultRejectedExecutionHandler() {
+        final ThreadPoolExecutor p =
+            new ThreadPoolExecutor(1, 2,
+                                   LONG_DELAY_MS, MILLISECONDS,
+                                   new ArrayBlockingQueue<Runnable>(10));
+        try (PoolCleaner cleaner = cleaner(p)) {
+            assertTrue(p.getRejectedExecutionHandler()
+                       instanceof ThreadPoolExecutor.AbortPolicy);
+        }
+    }
+
     /**
      * getRejectedExecutionHandler returns handler in constructor if not set
      */
@@ -1139,7 +1152,7 @@ public class ThreadPoolExecutorTest extends JSR166TestCase {
                     await(done);
                 }};
             for (int i = 0; i < 2; ++i)
-                p.submit(Executors.callable(task));
+                p.execute(task);
             for (int i = 0; i < 2; ++i) {
                 try {
                     p.execute(task);
@@ -1955,7 +1968,7 @@ public class ThreadPoolExecutorTest extends JSR166TestCase {
                     public void realRun() {
                         done.countDown();
                     }});
-            assertTrue(done.await(LONG_DELAY_MS, MILLISECONDS));
+            await(done);
         }
     }
 
@@ -2048,7 +2061,7 @@ public class ThreadPoolExecutorTest extends JSR166TestCase {
                 }
             }
             // enough time to run all tasks
-            assertTrue(done.await(nTasks * SHORT_DELAY_MS, MILLISECONDS));
+            await(done, nTasks * SHORT_DELAY_MS);
         }
     }
 
diff --git a/jdk/test/java/util/concurrent/tck/ThreadTest.java b/jdk/test/java/util/concurrent/tck/ThreadTest.java
index 92b2aca52a6..1cd9f0fbce4 100644
--- a/jdk/test/java/util/concurrent/tck/ThreadTest.java
+++ b/jdk/test/java/util/concurrent/tck/ThreadTest.java
@@ -76,7 +76,7 @@ public class ThreadTest extends JSR166TestCase {
      * setDefaultUncaughtExceptionHandler.
      */
     public void testGetAndSetDefaultUncaughtExceptionHandler() {
-        assertEquals(null, Thread.getDefaultUncaughtExceptionHandler());
+        assertNull(Thread.getDefaultUncaughtExceptionHandler());
         // failure due to SecurityException is OK.
         // Would be nice to explicitly test both ways, but cannot yet.
         Thread.UncaughtExceptionHandler defaultHandler
diff --git a/jdk/test/java/util/concurrent/tck/TreeSetTest.java b/jdk/test/java/util/concurrent/tck/TreeSetTest.java
index a37922e525b..55b28d613d9 100644
--- a/jdk/test/java/util/concurrent/tck/TreeSetTest.java
+++ b/jdk/test/java/util/concurrent/tck/TreeSetTest.java
@@ -69,7 +69,7 @@ public class TreeSetTest extends JSR166TestCase {
      * Returns a new set of given size containing consecutive
      * Integers 0 ... n - 1.
      */
-    private TreeSet<Integer> populatedSet(int n) {
+    private static TreeSet<Integer> populatedSet(int n) {
         TreeSet<Integer> q = new TreeSet<>();
         assertTrue(q.isEmpty());
         for (int i = n - 1; i >= 0; i -= 2)
@@ -84,7 +84,7 @@ public class TreeSetTest extends JSR166TestCase {
     /**
      * Returns a new set of first 5 ints.
      */
-    private TreeSet set5() {
+    private static TreeSet set5() {
         TreeSet q = new TreeSet();
         assertTrue(q.isEmpty());
         q.add(one);
diff --git a/jdk/test/java/util/concurrent/tck/TreeSubSetTest.java b/jdk/test/java/util/concurrent/tck/TreeSubSetTest.java
index 37edc1fb04c..a0f2b96ee57 100644
--- a/jdk/test/java/util/concurrent/tck/TreeSubSetTest.java
+++ b/jdk/test/java/util/concurrent/tck/TreeSubSetTest.java
@@ -60,7 +60,7 @@ public class TreeSubSetTest extends JSR166TestCase {
      * Returns a new set of given size containing consecutive
      * Integers 0 ... n - 1.
      */
-    private NavigableSet<Integer> populatedSet(int n) {
+    private static NavigableSet<Integer> populatedSet(int n) {
         TreeSet<Integer> q = new TreeSet<>();
         assertTrue(q.isEmpty());
 
@@ -79,7 +79,7 @@ public class TreeSubSetTest extends JSR166TestCase {
     /**
      * Returns a new set of first 5 ints.
      */
-    private NavigableSet set5() {
+    private static NavigableSet set5() {
         TreeSet q = new TreeSet();
         assertTrue(q.isEmpty());
         q.add(one);
@@ -94,7 +94,7 @@ public class TreeSubSetTest extends JSR166TestCase {
         return s;
     }
 
-    private NavigableSet dset5() {
+    private static NavigableSet dset5() {
         TreeSet q = new TreeSet();
         assertTrue(q.isEmpty());
         q.add(m1);
diff --git a/jdk/test/java/util/concurrent/tck/VectorTest.java b/jdk/test/java/util/concurrent/tck/VectorTest.java
index 78c236402f6..1878a78cc93 100644
--- a/jdk/test/java/util/concurrent/tck/VectorTest.java
+++ b/jdk/test/java/util/concurrent/tck/VectorTest.java
@@ -33,11 +33,9 @@
  */
 
 import java.util.Vector;
-import java.util.Collection;
 import java.util.List;
 
 import junit.framework.Test;
-import junit.framework.TestSuite;
 
 public class VectorTest extends JSR166TestCase {
     public static void main(String[] args) {